Improve parsing of existing metadata for nested AP

src/coscine/metadata.py

@@ -1213,19 +1213,19 @@ class MetadataForm:
             }
         }
 
-    def _parse_items(self, items: list[dict], parent_root: str = "") -> None:
-        root_paths = self.paths()
+    def _parse_items(self, items: list[dict]) -> None:
+        # Select the smallest lexicographic blank node guid
+        active_root = min([i["root"] for i in items])
         for item in items:
             path: str = item["path"]
             value: str = item["value"]
             root: str = item["root"]
-            if parent_root and root != parent_root:
-                continue
-            if path in root_paths:
+            if root == active_root:
                 field = self.path(path)
                 if field.is_inherited:
                     form = field.metadata_form()
-                    form._parse_items(items, value)
+                    subitems = list(filter(lambda e: e["root"] == value, items))
+                    form._parse_items(subitems)
                     field.append(form)
                 else:
                     field.append(value, True)
@@ -1235,4 +1235,4 @@ class MetadataForm:
         Parses existing metadata that was received from Coscine.
         """
         self.clear()
-        self._parse_items(data.items(), "")
+        self._parse_items(data.items())